Level 2 Help for DIFPIC

If no output file is specified, DIFPIC operates in a faster mode and only
prints the number of different pixels.

The value of RETVAL will be the sum of all comparisons (label, history
label, binary header, line prefix, and pixel). 
Individually, if a comparison finds no difference, its return value is
0. Otherwise, it's 1 for property label, 2 for binary header, 4 for
history label, 8 for line prefix, and 16 for pixel.

Standard Vicar size field:
  (SL,SS,NL,NS)
You can enter SL,SS,NL,
and NS together as SIZE, OR
enter the SL,SS,NL, and NS
parameters separately.
By default, the entire input
image is used if these
parameters are not entered.

Standard Vicar Bands field:
  (SB,NB)
You can enter SB and NB together
as BANDS, OR enter the SB and NB
parameters separately.
By default, the entire input
image is used if these

Number of bands: This may be used for multi-band (3D) images.  The default is
the number of bands in the input image label.

MOD is an option for byte images that is useful when one wants to see in the 
output file the location of all pixels for which the input DNs are not the 
same.  When MOD is specified for byte images, all pixels with the same input
DNs will have an output DN of 0, and all pixels that do not have the same input
DNs will have an output DN that is not 0.  MOD has no effect except for BYTE 
images.  MOD is recommended for byte images when an output file is produced.

For byte data if the difference computed is less than 0, the output DN is set
to 0 if MOD is not specified, but is set to 256 plus the difference if MOD is
specified.  This amounts to taking the difference modulo 256.

Specify if the label diff, binary header diff and line prefix diff should print
the differences found to console (VERBOSE) or not (SILENT).

List labels that should be ignored when comparing images. Ignored labels are
treated as if they are don't exists in the image and thus ignored labels with
different values or missing in one image are not considered when determining
if the labels between the given images differ.

Currently, this option is unimplemented, and always return false (different).

List properties that shoule be ignored when comparing images. All labels from
these properties are ignored and the images are considered same if all the
labels under the remaining properties are same.

Mapping of BLTYPE keyword to update-to-date version of binary header FMT
file for every project.

Mapping of BLTYPE keyword to update-to-date version of line prefix FMT file
for every project.

List of line prefix fields to ignore. The name of a field appears in dot
notation. For example, if you have column named 'A', and another column
named 'B' inside 'A', to refer to 'B', you use 'A.B'. If there are more
than one column that can be referred to by the same name, then all of
those columns are ignored.

List of binary header fields to ignore. The name of a field appears in dot
notation. For example, if you have column named 'A', and another column
named 'B' inside 'A', to refer to 'B', you use 'A.B'. If there are more
than one column that can be referred to by the same name, then all of
those columns are ignored.